Soundproofed internal combustion engine



Sept. Z, 1969 A. SCHEITERLEIN ET Al- SOUNDPROOFED INTERNAL COMBUSTION ENGINE s Smets-sheet 1 Filed May 8, 1968 lin Venafd A, c/Lea te/ Zena 0. S/(azsaZc G Th @/L Sept- 2, 1969 A. scHElTr-:RLEIN ET AL 3,464,398

SOUNDPROOFED INTERNAL COMBUSTION ENGINE Filed May 3, 1968 5 Sheets-Sheet 2 Sept.2,1969 A.SCHE|TER| E|N ETAL 3,464,398

SOUNDPROOFED INTERNAL COMBUSTION ENGINE Filed May 3, 1968 5 Sheets-Sheet WLM@ A United States Patent O 3,464,398 SOUNDPROOFED INTERNAL COMBUSTION ENGINE Andreas Scheiterlein, Othmar Skatsche, and Gerhard Thien, Graz, Austria, assignors to Hans List, Graz, Austria Filed May 3, 1968, Ser. No. 726,422 Claims priority, application Austria, June 2, 1967, A 5,170/67 Int. Cl. F02b 77/00; F02f 7/00 U.S. Cl. 123-195 4 Claims ABSTRACT F THE DISCLOSURE An internal combustion engine in which the crankcase has a sound absorbing layer in the form of a sheeting consisting of an oil pan and upright walls protruding up and above the crankshaft center, with the latter having bearing blocks on the crankcase and bearing brackets with a connecting bridge interconnecting the bearing brackets.

The invention relates to an internal combustion engine soundproofed in the crankcase area. Conventional soundproofing for the arrangement of soundproofing covers in such places of the crankcase as are known to be potential noise sources due to the effect of the igniting power and mass forces. However helpful as a means for reducing sound irradiation, these conventional soundproong methods are inadequate if applied to powerful high-speed nternal combustion engines of recent design.

Another conventional method provides for the application of a soundprooiing coating directly to the outer walls of the crankcase. This actually effective method of attenuating noises is, however, objectionable as it involves simultaneous thermal insulation of the crankcase thereby impairing the transfer of heat to the environment to a considerable extent. Moreover, the application of a soundproofing coating to the crankcase is cumbersome and timeconsuming, apart from the fact that damage to the coating during installation operations is hardly avoidable.

It is an object of the invention to provide effective soundproong for internal combustion engines. According to the invention, the oil sump defining the lower portion of the crankcase is so designed as to provide a soundabsorbing sheeting comprising sidewalls rising over and above the crankshaft center and attached to the cylinder block with the interposition of soundprooling shims, the bearing brackets suspended from the crankshaft bearing blocks being interconnected by means of a bridge extending alongside the engine. In view of the fact that a considerable percentage of engine noises emanate from the crankcase and reach the outside via the sidewalls of the crankcase, it is the primary object of the invention to substantially reduce sound irradiation from the crankcase. The provision of upwardly protruding oil pan sidewalls makes it possible for the crankcase proper to be designed without sidewalls cast integral with its front and rear ends, the bridge interconnecting the crankshaft bearing blocks absorbing the torsional and bending stresses formerly taken up to a considerable extent by the sidewalls of the crankcase.

The oil pan proper can be designed as a nonvibrating sheeting with the oil contained in the pan helping to attenuate such vibrations as may occasionally occur. Another advantage of this embodiment of the invention resides in the effective heat transfer from the crankshaft area via the upwardly protruding sidewalls of the oil pan, in addition to .the fact that this kind of soundproofing according to the invention does not involve any increase in the weight of the engine.

3,464,398 Patented Sept. 2, 1969 ice According to a preferred embodiment of the invention the oil pan is open at its front end and carries a connecting flange attached to the flywheel flange with the interposition of a soft packing. According to the invention the upper rim of the oil pan can be designed as a connecting flange attached to a supporting flange protruding from the crankcase with the interposition of a soft packing.

According to a further embodiment of the invention the connecting bridge of the bearing brackets can be designed as a bend and twist-resistant oil sump. This design which is particularly convenient from the viewpoint of foundry practice affords the necessary stiffness for a crankcase lacking sidewalls. f

Further details of the invention will appear from the following description of two embodiments of the invention with reference to the accompanying drawing in which:

FIG. 1 shows a cross-sectional view of an internal combustion engine according to the invention with the cylinder head removed.

FIG. 2, a partial longitudinal cross-sectional view of the internal combustion engine on line II-II of FIG. l,

FIG. 3 a cross-sectional view of another embodiment of the invention, also with the cylinder head removed.

The crankcase 1 of the internal combustion engine comprises an upper portion 2, defining the cylinder block with the cylinder liners 3 and the bearing blocks 4 for the crankshaft S.

The lower portion of the crankcase 1 comprises bearing brackets 7 cast integral with a connecting bridge 6 extending alongside the engine and is screwed to the upper portion 2 of the crankcase rfom below by means of clamping screws 8 located on both sides of the crankshaft bearings. The bearing brackets 7 are centered on the upper portion 2 of the crankcase by means of a horizontal bearing surface 9 including the crankshaft axis and by vertical bearing surfaces 10 provided on both sides of the crankshaft bearings. In the embodiment illustrated in FIG. l the connecting bridge 6 is designed as a bend and twist resistant sump with an arcuate bottom 11 and with sidewalls 12 with reinforced upper rims.

To the front end of the crankcase 1 the flywheel flange 1.4 is secured by means of bolts 15 with the interposition of a stop plate 13. The ywheel secured by means of bolts 16 to the extremity of the crankshaft 5 is designated by reference number 17.

In contrast to conventional types of engines the crankcase 1 of the internal combustion engine according to the invention does not feature any sidewalls cast integral with its front and rear ends but owes the stiffness required for the absorption of torsional and bending forces to a bridge 6 interconnecting the bearing brackets 7. In order to provide an oiltight sealing for the crankcase 1 and to preclude sound irradiation from the cuter surfaces of the crankcase, the oil pan 18 of the internal combustion engine is provided with sidewalls 19 protruding upwardly over and above the crankshaft center. The upper rim of the sidewalls 19 is designed as an outwardly angleshaped horizontal connecting flange 20 secured by means of bolts 23 with the interposition of soundproofing packings 21 to a supporting flange 22 laterally protruding from the upper portion 2 of the crankcase. In the embodiment shown in FIGS. l and 2 the sidewalls 19 of the oil pan 18 present spyholes 26 covered by attachable lids 24 and sealed by means of O-rings 25.

The oil pan 18 is open on the side facing the flywheel 17 and provided with an outwardly angle-shaped connecting flange 27 which is secured by means of bolts 29 with the interposition of a soundproofing packing 28 to the protruding rim of the stop plate 13 in the proximity of the flywheel flange 14. The lower portion of the oil pan 18 defines an oil reservoir 30 with an outlet 31.

The internal combustion engine illustrated in the drawing features a number of additional noise-attenuating devices which are not, however, subject matters of the present invention. This applies to the arrangement of socalled baffles around the flywheel ange, the cylinder block and the auxiliary machines associated with the internal combustion engine. As in the present instance, these can be made of sandwiched metal sheets. For example, the sandwiched plates 32 encompassing the flywheel flange 14 are screwed to the flywheel flange 14 with the interposition of soundprooiing shims 33. Likewise, the sandwiched plates 34 are secured to the front end of the cylinder block in a similar manner. Additional sandwiched plates 35 and 36 serve to screen the cylinder block off on both sides.

The internal combustion engine shown in FIG. 3 differs from the design illustrated in FIGS. 1 and 2 essentially by the reinforced construction of the crankcase in the area of the crankshaft bearings. The bearing brackets 7' as well as the bearing blocks 4' of this type of engine are wider and interconnected by means of two pairs of bolts 8 and 8 respectively, the connecting bridge 6' with its sidewalls 12 and the bearing brackets 7 forming a continuous box-type frame profile of remarkable stiffness. The remaining details of the internal combustion engine are identical with those of the type illustrated in FIGS. 1 and 2.

Obviously, several variants of design differing from the one hereabove described and illustrated in any by the accompanying drawings are feasible within the scope of the present invention. In particular, there is no limitation as to the design and attachment of the oil pan to the cylinder block, provided the primary requirement of an oil-tight and at the same time sound-proofing connection between the oil pan and the. crankcase is met.

We claim:

1. An internal combustion engine comprising a crankcase featuring a sound-absorbing sheeting, the said sheeting consisting of an oil pan adjoining the lower portion of the crankcase and comprising upright sidewalls protruding upwardly over and above the crankshaft center, the free rim of the said oil pan being secured to the crankcase, soundprooiing shims arranged between the said rim of the oil pan and its attachments to the said crankshaft, further comprising bearing blocks for the said crankshaft on the said crankcase, bearing brackets suspended from and attached to each of the said bearing blocks, a connecting bridge ext-ending alongside the engine and interconnecting the said bearing brackets.

2. An internal combustion engine according to claim 1, comprising a flywheel iiange, a stop plate secured to the said flywheel flange, the said oil pan being open on the side facing the flywheel ange and secured to the said stop plate, a soft packing being inserted between the rim of the oil pan and the open front end of same and the said stop plate.

3. An internal combustion engine according to claim 1, providing a connecting ange formed by the upper rim 'of the said oil pan, a supporting flange protruding laterally from the said crankcase, the said oil pan being secured with its connecting flange to the said supporting flange of the crankcase, a soft packing inserted between the said connecting ange and the supporting ange of the crankcase.

4. An internal combustion engine according to claim 1, wherein the said connecting bridge of the bearing brackets is designed as a bendandtwistresistant sump.

References Cited UNITED STATES PATENTS 1,602,089 10/ 1926 West. 1,759,147 5/ 1930 Vincent. 2,340,885 2/ 1944 Kinnucan. 3,046,954 7/ 1962 Hoffman et al. 3,195,530 7/1965 Heidner 123-198 3,412,724 11/ 1968 Scheiterlein et al.

WENDELL E. BURNS, Primary Examiner U.S. C1. X.R. 

